Beachhead - Languages—Some Dead and Some Still Kicking
“maddog”, rang out the voice that I knew very well. It belonged to one of my young friends, Eduardo. “Why did you name your boat Agape? Is it because the boat is wide open?”
I stopped sanding my little sloop and faced my young friend. “No, the word is not English, but Latin. It is not meant to rhyme with a small fruit that is used in wine, but to speak of the highest form of love.”
Eduardo looked at me a moment and said, “I did not know that you spoke any languages other than English.”
“For the most part, I do not”, I answered. “I studied Latin and French in grade school many decades ago, but by the time I understood how valuable it was to know multiple languages, most of that training had slipped away. Yet, having studied Latin and French does come in handy from time to time, as I sometimes use that forgotten training to understand new words both in foreign languages and my native English. Now, the languages I study are mostly computer languages.”
“That is another thing”, said Eduardo. “Why are there are so many languages when all you really need is Java?”
I put down my sanding block, leaned up against the Agape and thought carefully for a little while.
FORTRAN was the first computer language I ever learned. It was in 1969, and I learned FORTRAN by reading a book called Programming the IBM 1130 in FORTRAN and practicing on an IBM 1130 computer system that had 4,000 words of main memory and a card reader and punch. The system also had a chain printer (you probably do not want to know what that was) and a pen plotter. Notice that the name of the language was FORTRAN, in all capital letters. That is how we wrote it in that day, for it stood for FORmula TRANslator, just like COBOL stood for COmmon Business Oriented Language. FORTRAN was for engineers and scientists, and COBOL was for business people. Both languages did their jobs fairly well.
Because I was an engineering student and a co-op for the Western Electric Corporation (a member of the Bell System), I learned FORTRAN. Somewhere along the line, marketing people decided that people did not like all capital letters in names, so the language became called Fortran. Through the years, FORTRAN (which started in the early 1950s) became FORTRAN II, FORTRAN III, FORTRAN IV and then started to use names related to the years that it was updated. Today, work is being done for a definition for Fortran 2008. Fortran is a good example of a language (and not just a name) that changed to meet the needs of the time.
After returning to Drexel Institute of Technology (now Drexel University) from my co-op period, I started seeking out more of those devices known as computers. I found several Digital PDP-8 mini-computers in a computer lab of the Electrical Engineering Department. Although these systems had a small language that was FORTRAN-like, called Focal, the PDP-8 mini-computers at Drexel were mostly programmed in assembly and/or machine language, the ones and zeros that the machine used.
I was given some books on how to program the PDP-8 in machine language, and I taught myself how to program using the most fundamental language of the computer. Fortunately for me, the machine language of the PDP-8 was a very simple one, having only eight basic instructions and one main register that acted as an “accumulator”. Each instruction was the same length and matched the word size of 12 bits, so the PDP-8 was simple, though tedious, to program. The PDP-8 could not subtract (much less multiply or divide), so you had to add the two's complement of the subtrahend in order to subtract.
The processors had switches and lights on the front panel, and by toggling these switches you could input the program directly into the memory of the system. More important, you could step through your program one machine language instruction at a time, seeing the results of each instruction on the accumulator of the machine and in the program counter (also designated by lights on the console).
Most people did not enter their entire program through the switches, of course; they used an ASR-33 Teletype to enter the source code of the assembly languages into an editor, punched out a source-code paper tape, input that tape to an assembler and (finally) got an object-level tape punched that would contain the 1s and 0s to be fed into the computer.
One turnaround of your program typically took 45 minutes at a minimum. It took five minutes to read in the editor (paper tape). Next, you typed in your program, did a few edits and punched out your program onto new paper tape. Then, you read in the three-pass assembler (15 minutes of paper-tape reading), read in your source-code program (assuming your paper tape did not rip) and punched out the binary (paper) tape that contained your program.
Finally, you read your binary paper tape into the memory of the computer, watched while the program probably over-wrote itself and everything else in real memory, and then you started the whole process over again (after cursing loudly at the programming gods).
But, it was fun and a challenge. And, it was the “will of the machine” versus the pure logic of 1s and 0s. I was hooked.
During this same period, I switched from being an Electrical Engineer to a major that was both engineering and business, with a minor in what became Computer Science. I studied several different languages: Algol, Lisp, PL/I, SNOBOL and APL, each one with its own special niche in the computer field.
I remember SNOBOL as a language for string processing, and although I do not remember much of it, I do remember thinking that almost any string of characters input into a SNOBOL compiler would generate some type of syntactically correct program. I remember thinking that the only syntax error that might be generated was the lack of the END statement.
APL, on the other hand, was an array programming language that was very powerful. It even fostered its own special set of symbols that meant you had to paint them on the side of the keys of your regular keyboard, and (in the case of an IBM Selectric typewriter) use a print head specially made for APL.
In a class on comparative language design, our professor gave us a challenge of re-implementing a 40-line FORTRAN program in as few lines of APL as possible. Most of us reduced the FORTRAN program to three lines of APL, some to two lines of APL. And, one of the brightest students in the class (David Erb) had stayed up the entire night reducing the program to only one line of APL. It was a truly amazing line of code.
After inputting the data to the program and seeing the correct result, the professor (with a gleam in his eye) asked David to explain how the program worked. David, having finished the program only hours before, tried desperately to remember how it actually worked, but he could not explain how he had come to that particular single line, or even how it would produce the desired result.
As a class, we had experienced our first “write-only” language. It was a lesson remembered over the next 38 years—never write a program you could not easily change or re-use.
It was an interesting time in the days before Computer Science degrees. It was more like “Computer Black Magic”, where the computers were owned by the Math Department, the Electrical Engineering Department, the Business school, the Physics Department and so forth. I even had one professor who told me I never would be able to make a living writing software. It has yet to be seen if he was correct.
And, as time went on and computers became more and more important to the world, universities started granting Computer Science, Computer Engineering, Network Engineering and Information Science degrees. And, what we experienced as very painful steps toward understanding these procedures became formalized into what we now call (generally) Computer Science.
I eventually graduated from Drexel University, and in looking for my first job, I was determined that I would not program in a “higher-level language”, such as FORTRAN or COBOL. I wanted to program in assembly language. I turned down many jobs, looking for that chance.
Eventually, that chance came to me: to program in the systems programming group of Aetna Life and Casualty in Basic Assembly Language (BAL) for the IBM 360 series computer—an assembly language and computer system I had never seen before. They asked me if I could program it in assembly language. I said, “Sure, just show me the book.”
Fortunately there was a book, Programming the IBM 360 in BAL, and after reading it and practicing a few days at Aetna, I started a four-year career of system programming there—a time in my life where I learned many, many things.
The one “language”, if I may call it that, which sustained me over the years, however, was the 1s and 0s of machine code.
It was machine code that allowed me to learn how compilers and interpreters can translate different languages to what the machine can follow. It was machine code that showed me how reentrant and recursive languages worked, and how minute changes in the code of a program could cut many minutes, if not hours or days, off a program's execution.
It was the study of machine code and machine architecture that allowed me to know how the operating system really worked, and allowed me to understand the protocols of networking. And, it was machine code and looking at the sources of it that let me understand the issues of big-endian versus little-endian and single-precision versus double-precision.
And, it was the knowledge of machine language that allowed me to find places where the compilers had made mistakes in doing the translation of source code to those 1s and 0s. People who knew only higher-level languages could have kept looking at the source code of those high-level languages forever and would not have found the problems.
Nevertheless, other than brief excursions into teaching machine and assembly language courses (the last time was in 1985 when I taught a course in PDP-11 assembly language, another assembly language that I taught myself), I have not actually written in assembly or machine language since I left Aetna in 1977.
The simple reason is that it takes too long to write in those low-level languages, and it is too error-prone. Compiler optimization techniques have gotten better, CPUs faster, memories cheaper and people's time more expensive. Don't get me wrong; there still are plenty of places where assembly language and machine code are used, particularly in places that need absolutely the best performance or the smallest size. But overall, the compilers are doing a pretty good job, and the average person's mind does not adapt well to the tedious task of writing in assembly.
Yet, when I do sit down and write a bit of code in some modern language, I do two things:
I think about whether there is a language that can do the program better and in a clearer, more human-maintainable way.
I think about what that language may be generating in machine language and whether changes to the source code or to the algorithm or to the way the data is positioned in memory might affect the speed at which the program runs.
A friend of mine, David Mossberger, once did a study of multiplying two very large arrays. One multiplication was done in the standard linear-algebra “textbook” fashion of analyzing rows and columns. The second multiplication took into account the cache of the CPU and memory, knowing how the 1s and 0s were arranged. The second multiplication took one-fortieth of the time on an Alpha processor (which had large cache memories), and one-tenth of the time on an Intel processor (with smaller cache memories).
During the years, I have been exposed to many new languages and many new technologies. I have been able to understand each and every one because I stop to think about what the 1s and 0s are doing. There have been few new computer technologies that have stumped me in the past 38 years.
This is why I object to colleges and universities who feel that high-level languages, such as Java (or Python, or PHP, or you name it) are the only languages worth teaching, and that machine and assembly languages are not worth teaching to students.
In the end, it all comes down to 1s and 0s, and if you do not know what they are doing, and how the machine actually works, you are at the mercy of others.
In a lot of ways, machine code and assembly language are like Latin—perhaps little used, but still useful to know for the serious language enthusiast and programmer.
Carpe diem from the Agape.
Jon “maddog” Hall is the Executive Director of Linux International (www.li.org), a nonprofit association of end users who wish to support and promote the Linux operating system. During his career in commercial computing, which started in 1969, Mr Hall has been a programmer, systems designer, systems administrator, product manager, technical marketing manager and educator. He has worked for such companies as Western Electric Corporation, Aetna Life and Casualty, Bell Laboratories, Digital Equipment Corporation, VA Linux Systems and SGI. He is now an independent consultant in Free and Open Source Software (FOSS) Business and Technical issues.